Flexible door with spaced leaf springs



Jan. 7, 1969 A. DIRUBBO 3,420,290

FLEXIBLE DOOR WITH SPACED LEAF SPRINGS Filed Feb. 3, 1967 r i E; 3 O\ I I INVENTOR. ANGELO DI RUBBO Pan/mow "EMA-aw ATTORNEYS United States Patent 3,420,290 FLEXIBLE DOOR WITH SPACED LEAF SPRINGS Angelo Dirubbo, North Chelmsford, Mass., assignor to A & D Fabricating Company, Inc., Lowell, Mass, a corporation of Massachusetts Filed Feb. 3, 1967, Ser. No. 613,816 US. Cl. 160354 9 Claims Int. Cl. E06b /00 ABSTRACT OF THE DISCLOSURE This invention relates to flexible doors of the type used indurtrially and commercially to permit the passage of hand trucks or the like while substantially sealing the door opening from drafts.

Flexible doors of this type are usually formed of rubber or plastic sheets with a partial, or skeletonized framing of inflexible or flexible material. One such type includes an inverted L shaped inflexible frame, the horizontal upper portion supporting a single sheet, the vertical portion being hinge pivoted to the door frame and the lower edge and free vertical edge being unframed and flexible. Such a door is shown in my Patent 3,272,257 of Sept. 13, 1966. Another such type includes two paral- 161 sheets of flexible material the frame consisting of flexible, resilient members at perimeter portions of the top, bottom and two sides of the door body and also including crosswise flexible, resilient separators or fillers. Such a door is shown in US. patents to Eckel No. 2,720,920 of October 1955 and No. 2,815,808 of Dec. 10, 1957.

It has also been proposed to combine with a door of the above first mentioned single sheet type, a plurality of vertebra-like members held together by a coil spring tensioning member for flexibly stiffening the door.

In this invention, the inverted L shaped frame has been eliminated and the flexible door is of the two ply, parallel sheet type. However, the skeletonized rubber peripheral framing, and cros filling of the prior art is not used, since such doors have tended to sag and wrinkle in use. Instead thereof, the two ply door of this invention includes a vertical support of stiff, non-resilient material such as wood, or metal, along one side, the support being hinge pivoted to a door frame to swing open and closed. A similar stiff, non-resilient support is provided along the other, or free, vertical edge and extending crosswise between the vertical supports are an upper, a lower, and preferably anintermediate, single leaf, rectangular strip, metal spring. Each such spring is firmly secured at each opposite end to one of the vertical supports, the inflexibility of the leaf spring in a vertical direction assuring no sag in the cantilevered door. However, the door remains resiliently flexible in a horizontal direction so that the rubber panels and leaf springs can flex along vertical lines as a unit while also pivoting along the vertical hinge pivots. Because of the thinness of the leaf springs, filler means is mounted along each spring, with the sheets secured to the filler means for maintaining parallelism and avoiding wrinkles. The doors of this invention will thus flex from top to bottom as a unit 3,420,290 Patented Jan. 7, 1969 along vertical flex lines to permit a person to pass through or will both flex and hinge to permit a vehicle to pass through.

The principal object of the invention is to provide a two ply rubber door with vertically spaced apart single leaf, spring cross members attached to the rubber sheets, so that the entire panel flexes as a unit along vertical lines of flex.

Another object of the invention is to provide such a door with grooved wood block fillers along each crosswise, thin, elongated metal strip spring so that the heavy rubber sheets may be secured to the blocks and the springs without danger of sag.

A further object of the invention is to provide a stuffed, two ply flexible door with flexible resilient cross braces which cannot yield downwardly but which freely yield in a horizontal direction, thereby eliminating the need for inverted L shape framing.

Other objects and advantages of the invention will be apparent from the claims, the description of the drawing and from the drawing in which:

FIGURE 1 is a front elevation of a flexible door constructed in accordance with the invention, with parts broken away.

FIGURE 2 is a sectional view on line 2-2 of FIG- URE 1.

FIGURE 3 is a plan view in section on line 33 of FIGURE 1, on an enlarged scale.

FIGURE 4 is a fragmentary front elevation of one of the leaf spring means of the invention, on an enlarged scale, and

FIGURE 5 is a fragmentary, perspective view of another embodiment of the leaf spring and filler means of the invention.

As shown in the drawing, the flexible door 25 of the invention may be single or double, and forms a closure in a suitable door opening 26 which may lead to a cold room, a loading platform or similar location. Each door 25 is of the two ply, or stuffed, type and comprises a flexible panel 27 formed by two parallel rectangular sheets 28 and 29, each of flexible, rubber-like sheet material such as rubber or plastic. Each panel 27 includes the opposite, vertical edge portions 31 and 32, top edge portion 33 and bottom edge portion 34, the vertical edge portions 31 and 32 being the longer sides of the rectangular panel.

A pair of spaced apart, vertical supports are provided, the first such support 36 extending from top to bottom of the panel with the vertical edge portions 31 of each sheet securely aflixed on the outside thereof by bolts, or rivets 37 so that the support 36 is sandwiched between the sheets 28 and 29. The stiff support 36 may be of wood or metal and is secured to the hinge pivot means 38, also by bolts 37, so that the door may hingedly open and close in the manner of my said patent and as disclosed therein. The second such vertical support 39, also extends from top to bottom of the panel, between the vertical side edge portions 32 of the sheets 28 and 29, the sheets being firmly secured thereto by bolts, or rivets, 40 to sandwich the support 39 therebetween. Support 39 is also, preferably of stiff non-resilient material such as wood or metal. An air space 41, of predetermined width, equal to the thickness of the support 39, is thus formed between the sheets 28 and 29.

A plurality of individual, single leaf, or rectangular plate type, springs 43, 44 and 45, preferably of thin spring metal of substantial vertical dimension such as three or four inches, extend crosswise, or transversely, between sheets 28 and 29, in air space 41, all in a common plane. Spring 43 extends between the top edge portions 33 of the sheets, spring 44 extends between the bottom edge portions 34 of the sheets and spring 45 extends transversely, intermediate of the height of the sheets. =Each opposite end 46 and 47 of each spring such as 43, 44 or 45 is firmly secured to one of the vertical supports 36 or 39 by bolts or rivets 48, 37 or 40 so that the free, swingable portion of the panel is inflexible downwardly and assured of cantilever supoprt without sag.

The springs 43, 44 and 45 are vertically spaced apart a substantial distance and there may be two or three intermediate springs if desired.

Filler means 50 is preferably provided mounted along each spring and flexible horizontally therewith. Preferably means 50 comprises a series of identical blocks 51, 52 and 53 of solid, stiff non-resilient material such as wood. Each block is beveled along its opposite vertical edges 54 and 55 and grooved at 56 in its under edge 57, the block being straddled on the spring with the spring received in the groove. Bolts, or rivets, 58 are passed through countersunk holes in the blocks and through the springs, and the edge portions of the sheets 28 and 29 are secured to the outer faces of the blocks by a suitable adhesive layer 59 so that the sheets are maintained and supported in parallelism Without wrinkles. The straddle position of the blocks, is of great assistance in assembling the doors, reducing cost and time of manufacture considerably because they can be slid on the springs and will remain in position while the bolting is completed.

As shown in FIGURE 5, filler means 50 may comprise a pair of rubber strips 60 and 61, each secured on an opposite side of a spring 43, 44 or 45 to fill the space between the thin spring and the heavy rubber sheets. However, wood blocks are preferred as oflering more support to the sheets, without deformation or strain in a vertical direction.

The remainder of air space 41 is usually filled with a foam filler 62, of any well known type, and the panel 27 may be provided with a window 63 if desired. A nose piece 64 of rubber may also be provided on the free terminal edge of each panel, or in smaller doors the sheets 28 and 29 may be unitary and bent to form a nose piece as shown in FIGURE 5.

I claim:

1. A flexible door comprising:

a flexible panel of sheet material, said panel having opposite vertical edges;

a first stiff, non-resilient support afflxed along one opposite vertical edge of said panel;

hinge pivot means, secured to said support, for hinge pivoting said door;

a second stiff, non-resilient support atfixed along the other opposite vertical edge of said panel, and

a plurality of individual, single leaf, rectangular flat strip springs, spaced apart a substantial distance vertically from each other in a common plane, each leaf spring extending transversely of said panel and aflixed, at each opposite end, to one of said supports;

said springs being inflexible vertically to support said panel but being flexible horizontally to permit flexing of said panel in horizontal directions.

2. A flexible door as specified in claim 1 wherein:

said flexible panel is formed of a pair of parallel, rubber-like sheets having an air space therebetween; said supports are affixed between said sheets;

said leaf springs extend between said supports in said air space and a foam filler occupies the remainder of said air space.

3. A flexible door as specified in claim 1 wherein:

said flexible panel is formed of a pair of parallel rubher-like sheets each aflixed to the outside of said supports to form an air space therebetween of predetermined uniform width;

said leaf springs are of thin sheet metal, of less thickness than said predetermined width, and

filler means is mounted along each said spring for maintaining and supporting said pair of sheets in parallelism.

4. A flexible door as specified in claim 3 wherein:

said filler means comprises a pair of strips of rubberlike sheet material each mounted on an opposite side of one of said springs and each secured to said sheets.

5. A flexible door as specified in claim 3 wherein:

said filler means comprises a plurality of blocks of stiff, non-resilient solid material, mounted along at least one side of each said spring, at spaced distances therealong, and each secured to the adjacent portion of said rubber sheets.

6. A flexible door as specified in claim 3 wherein:

said filler means comprises a plurality of identical blocks of rigid material, mounted at spaced distances along one of said springs;

each said block having a groove in the underside thereof, receiving said spring therein, and

each said block being secured to the adjacent portions of said sheets to firmly support the same in parallelism.

7. A flexible door comprising:

a pair of spaced, vertical supports;

a pair of parallel rectangular, flexible sheets, each having the longer side edge portions thereof aflixed to the outside of said supports to form a two ply, hollow, flexible door panel;

at least two thin, flat, planar, strip springs, one said spring extending across the top of said panel between said sheets, and having each opposite end thereof fixed to one of said supports and the other said spring extending across the bottom of said panel between said sheets, and having each opposite end thereof fixed to one of said supports, and

pivot means on one of said vertical supports for hinge pivoting said flexible door,

said spring being of metal-like material inflexible in a direction parallel to the plane thereof but flexible in a direction normal to the plane thereof.

8. A door comprising:

a pair of parallel, flexible sheets of rubber-like material,

each having vertical edge portions;

a stiff resilient support extending between the vertical edge portions of said sheets, along one side thereof and secured thereto;

hinge pivot means on said support for pivotally mounting said door;

at least two individual thin, flat, metal single leaf springs extending transversely between said parallel sheets, one at the top and one at the bottom thereof, one end of each said spring being fixed to said stiff resilient support;

and filler means, mounted along each said thin single leaf spring for maintaining and supporting said sheets in parallelism, said means being adapted to flex with said springs.

9. A combination as specified in claim 8 wherein:

said filler means comprises a series of spaced apart, groved wood blocks, each straddling said spring and beveled on each end thereof to permit such flexing while in abutting end to end relation with adjacent blocks.

References Cited UNITED STATES PATENTS 1,172,800 2/1916 Johnson 354 X 1,628,651 5/1927 Burress 49-9 2,720,920 10/1955 Eckel 160354 2,783,833 3/1957 Cann 160354 2,815,808 12/1957 Eckel 160-354 3,090,425 5/1963 Carlo 16040 X 3,212,561 10/1965 Eckel 160-354 DAVID J. WILLIAMOWSKI, Primary Examiner. DENNIS R. TAYLOR, Assistant Examiner. 

